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Old 14th Sep 2021, 9:53 am   #19
woodchips
Octode
 
Join Date: May 2010
Location: Grantham, Lincolnshire, UK.
Posts: 1,177
Default Re: Valve testers & 'soak' testing.

This is interesting, thanks. Can we take it a little further please.

Leakage at PIV, valve hot or cold? If DC then is it polarity specific? Leakage similar between anodes? Why should it leak? Glass is a good insulator, does it leak between any two pins, connected or not? What, basically, is the failure mode.

Emission imbalance, normally the cathode has more than enough coating to supply the number of electrons, so would this be an indication that the valve is near end of life?

With a rectifier one assumes that each half is used, worn out, equally which is not the case with a DT. Back in the 70's our TV failed to sync lock, reading as to why it was the sync separator failing due to low anode current, fix was to swap it with another similar valve.
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